The present invention relates to an excess slip control device for a driving wheel, and more particularly to a control device for controlling excess slip of the driving wheel by controlling fuel supply to an engine and controlling an ignition timing.
In a conventional excess slip control device for a driving wheel, a slip condition of the driving wheel is detected according to a driving wheel speed or the like, and when a predetermined slip condition is detected, fuel supply to an engine is suppressed (cut, for example) to reduce an engine output, thus preventing the excess slip of the driving wheel. Such a control device has been proposed by the present applicant in Japanese Patent Application No. 62-145920, for example. In this control device, when a predetermined slip condition is detected, stop of fuel supply to the engine (which will be hereinafter referred to as fuel cut) and reduction of the fuel supply is alternately repeated so as to prevent an operational shock due to rapid decrease in engine torque and improve the drivability.
However, in the above prior art device, when the operational condition is shifted to a fuel cut region that is a region where the predetermined slip condition is detected, or the operational condition is shifted from the fuel cut region, a fuel quantity to be supplied to the engine is largely fluctuated. As a result, a fluctuation in engine torque cannot be sufficiently prevented, and it is yet necessary to improve the suppression of the operational shock. Further, even when it is determined that the fuel cut should be carried out, the fuel cut is not carried out with respect to any cylinder in a compression stroke or an explosion stroke at the timing of determination, resulting in the generation of control lag.